1. Field of the Invention
The present invention relates to a fastening element for securing plate-shaped insulation materials and including a large-surface, flat clamping member, a hollow stem projecting from the clamping member and enclosing a hollow space that opens into an opening formed in the clamping member, and at least one plate-shaped cover for closing the opening and attached to the clamping member.
2. Description of the Prior Art
Insulation materials, in particular, insulation boards are used for heat insulation and partially also for noise insulation of walls and ceilings. Conventionally, the insulation boards are secured to a raw masonry. For securing the plate-shaped insulation materials, fastening elements, which have a large-surface, flat clamping plate from which a stem projects, are used. The stem extends into the insulation board. The fastening element is secured to the masonry primarily with a dowel-like or nail-like anchoring member that forms an extension of the stem. The dowel-like anchoring member is inserted in a pre-drilled bore formed in the masonry and in anchored in the masonry bore by being expanded. A nail-like anchoring member is directly driven into the masonry, without preliminarily forming a bore in the masonry. A bore formed in the stem and opening into the clamping member insures access for an expansion screw or a similar expansion member used for expanding the dowel-like member or to a nail-like member. After the masonry is covered with the insulation material plaster is applied.
The dowel-like anchoring member can, e.g., be formed integrally with the hollow stem. However, primarily, dowel sleeves are used which are inserted through the hollow stems and project therefrom.
It is important that the plaster material does not penetrate into the inner space of the hollow shaft as this can result in formation of a cavity in the surface of the applied plaster layer. If the plaster material and, thereby, moisture penetrates in the interior of the hollow stem, the moisture can cause corrosion of the anchoring member. In addition, there is a danger of formation of thermal bridges which adversely affect functioning of the insulation.
The prior art discloses proposals to close the opening in the clamping member that would permit to prevent the penetration of the plaster and moisture into the interior of the hollow stem. E.g., U.S. Pat. No. 5,118,235 suggests to close the opening with a cover which is connected to the clamping member for a pivotal movement about an axle arranged in the region of the opening. In the closed position, the pivotal cover cooperates with a projection extending from an inner wall of the hollow stem. With this cover, there is a danger that during closing or during application of the plaster, the cover would be inserted so deep that the opening would not be corrected closed. On the other hand, if the cover is not adequately inserted into the opening, the cover would protrude. As a result, the opening again would not be adequately closed. During plastering, the cover can be open even more in the later case. With an inadequate closing of the opening, the plaster material and moisture can penetrate into the inner space of the hollow shaft. In addition, the cover itself is an obstacle to the application of plaster when it protrudes from the opening. This can bring undesirable results. In the open position, the pivotal cover can occupy a random position. On many occasion, the cover partially covers the opening. This presents an obstacle to driving-in of the anchoring member and forces a worker to keep the cover away with one hand while placing the anchoring member into the hollow stem with the other hand.
Accordingly, an object of the present invention to eliminates the drawbacks of the prior art cover.
Another object of the present invention is to provided a fastening element for securing plate-shaped insulation elements which would insure a reliable closing of the opening.
A further object of the present invention is to provide a fastening element the cover of which, in an open position, would not hinder access to the interior of the hollow stem.
A still further object of the present invention is to provide a fastening element that can be simply and cost-effectively produced.